Original storage units of computers store the data by means of magnetic medium, floppy disks and hard disks now used in computers are both magnetic storage devices. Magnetic storage devices can be made large storage easily, but they are usually short-lived and unreliable. Furthermore, actual mobile storage devices can't be moved really, most of them can't be carried conveniently just because of their great cubage, such as external hard disk, external CD-writer, ZIP, MO, etc. These storage devices can be large storage capacity, but not mobile enough. As to portable storage device, such as floppy disk, not only the special driver for it is large in cubage, energy consuming and noise, but also it runs slow and physical damages easily. As the development of semiconductor, capacity of non-losable solid storage unit is becoming larger and larger, while the price of it is becoming lower and lower. Therefore, the replacement of floppy disks and hard disks by solid storage disks will greatly enhance the work of computer and data reliability. There are various solid storage disks in existence, such as CF card, MMC card, SMC card and non-losable solid storage units with USB interface. They communicate with PC via their own interfaces.
Because different card has different structure, PC must have various interfaces to access data from various solid storage devices listed above. This will not only add different electric connection interfaces to PC's mainboard, but also make PC and its peripheries complex.
Many standard data interfaces at present, such as USB or IEEE394, have been the new-style interfaces and widely used in PC. Non-losable storage medium such as flash memory is better than magnetic medium, and storage units based on it don't require complicated driver. So storage units based on such medium are replacing existing portable storage devices gradually.
On the other hand, integrated circuit card consists of one or more integrated circuit chips and is encapsulated to be a portable card. This card has the ability of temporary or permanent data storage, and data can be accessed from exterior or processed by itself. This card also has the ability of algebraic operation and logical operation, which can make it identify and respond external information and process data by itself. As an integrated circuit card, IC card is a card which has microprocessor, large storage, and other integrated circuit chip embedded in substrate made of plastic. It comes forth as the development of semiconductor and the demand for information security of people. Since the most advanced semiconductor-manufacture and information security technique are used in IC card, it has four characters in below comparing other cards: 1. Large capacity of storage: it has internal memory units, such as RAM, ROM, EEPROM, etc. the storage varies from several bytes to several million bytes. Much information, such as character, voice, picture and image, can be stored in the card. 2. High security: IC card achieves its security both by the hardware and the software. The character of accessing in different part of the card can be controlled respectively. Password can be set in storage units of IC card, and if accessed illegally, the card will destruct automatically, that is the card can not be read or written. 3. Less requirement of network: highly reliability and security of IC card reduce the requirement in real-time performance and sensitivity of computer network. This is good for using in the network which has bad quality.
Being reliable and safe, IC card is used wider and wider. IC card appears in financial products, private consuming products, etc. Thus, it is unavoidable that PC should integrate IC card under the circumstance of the increasing amount of IC card year after year. For the same reason, the demand for IC card reader will grow gradually. Because there has no IC card reader in present PC, these PC can't use IC card to identify information. Besides, communication interfaces in PC are limited, while existing data input are various both in type and manner, so there always have not enough interfaces in PC, and some external apparatus only can be plugged in by turns to communicate, or even can't be connected to PC directly.
At present, products based on above technique include USB memory, CF card reader, SMC card reader, and IC card identifier. Seen from designing and using, there neither has any common components adopted in above products, nor has any flexible combination of above products. Capacity or function of any kind of product is fixed, and can't be combined with each other. Then customers have to buy and use each respectively, and have no way to upgrade them. As to manufacturing products, the cost can't be reduced and output can't increase easily just because there has no appropriate modules for these products. Furthermore, in order to perform identifying, wireless data communicating, etc, PC is integrating more and more interfaces and data processing devices, but these configurations are not convenient.